expanding block

[sivlogkart]

I am not sure if this has a place on a lockpicking site but is is a lock bypass method that my brother and I have used for many years (for demo purposes only that is).

Often one finds open doors that a crimal might like to open later, and in some cases they can using an expanding block that they put in the hold in the door frame there the bolt goes. This block has to be small enough the door appears to close as normal.

Then later the crimal can come back and expand the block. We made blacks that would expand when wet for example so just a little water in the gap between the frame and door would work, and others that would expand with head, though these did not work as well.

[Chrispy]

(for demo purposes only that is).

Riiiiiiiight.....

[SFGOON]

What sorts of materiels would you use for this? I assume it's innefective against deadbolts, is it not? All in all a very good idea, thank you for sharing, but please elaborate.

[hung82000]

It should definitely be ineffective against deadbolts. I have seen people do this before, they've just used Kleenex, and don't have a need for it to expand, as it fills it enough to "bump" the frame to get it open.

[Minion]

Black ducttape works as well, if you can make it look hidden.

[sivlogkart]

First it was used only for demo purposes, as I do have this sites motivation for what I do!

Some of the suggestions for materials are fine. It depends a bit on the colour and look of the bolt hole. We often used soft wood, first held under water for say a day and then compressed until dry. This then returns partially to its orginal shape when wet again, but there are a number of other things that work.

I have often arranged permission to demonstrate a security weakness, and then given that I show how it is done, which is much more effective than just telling someone who will claim it will not work, particularly when they know they are talking to a mathematician!

I also do similar demo for computer networks, but then that is another story!

KJ